URL Loading System Programming Guide - Apple Developer

Using NSURLSession
Creating and Configuring a Session
NSString *cachePath = [NSTemporaryDirectory()
stringByAppendingPathComponent:@"/nsurlsessiondemo.cache"];
#endif
NSLog(@"Cache path: %@\n", cachePath);
NSURLCache *myCache = [[NSURLCache alloc] initWithMemoryCapacity: 16384
diskCapacity: 268435456 diskPath: cachePath];
defaultConfigObject.URLCache = myCache;
defaultConfigObject.requestCachePolicy = NSURLRequestUseProtocolCachePolicy;
/* Create a session for each configurations. */
self.defaultSession = [NSURLSession sessionWithConfiguration: defaultConfigObject
delegate: self delegateQueue: [NSOperationQueue mainQueue]];
self.backgroundSession = [NSURLSession sessionWithConfiguration:
backgroundConfigObject delegate: self delegateQueue: [NSOperationQueue mainQueue]];
self.ephemeralSession = [NSURLSession sessionWithConfiguration:
ephemeralConfigObject delegate: self delegateQueue: [NSOperationQueue mainQueue]];
With the exception of background configurations, you can reuse session configuration objects to create
additional sessions. (You cannot reuse background session configurations because the behavior of two
background session objects sharing the same identifier is undefined.)
You can also safely modify the configuration objects at any time. When you create a session, the session
performs a deep copy on the configuration object, so modifications affect only new sessions, not existing
sessions. For example, you might create a second session for content that should be retrieved only if you are
on a Wi-Fi connection as shown in Listing 1-3.
Listing 1-3
Creating a second session with the same configuration object
ephemeralConfigObject.allowsCellularAccess = YES;
// ...
2013-10-22 | Copyright © 2003, 2013 Apple Inc. All Rights Reserved.
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